I purchased a used 2011 Nissian Altima and used my 2006 Nissian Altima as a trade-in (whic has a balance of $4,500.00). I drove off the lot and the check engine light came on. I called the car dealer and I was told the car was pressure washed; which caused the light to come on. I went to the dealership told them I no longer wanted th car and I wanted my trade-in back; do to the engine problems that I wa never made aware of. I was told they sold my car. I am still currently pay monthly for my trade-in, and I was never given financing document to pay the 2011 Altima off. Do I have a valid case?